Mphamvu ya cellulose ether pa kutentha kwa hydration ya simenti yosiyana ndi ore limodzi

zotsatira za cellulose ether pa kutentha kwa hydration kwa simenti ya Portland, simenti ya sulfoaluminate, tricalcium silicate ndi tricalcium aluminate mu 72h anafaniziridwa ndi isothermal calorimetry test. Zotsatira zimasonyeza kuti mapadi ether akhoza kwambiri kuchepetsa hydration ndi kutentha kumasulidwa mlingo wa Portland simenti ndi tricalcium silicate, ndi kuchepa zotsatira pa hydration ndi kutentha kumasulidwa mlingo wa tricalcium silicate ndi zofunika kwambiri. Zotsatira za cellulose ether pa kuchepetsa kutentha kumasulidwa kwa hydration ya sulfoaluminate simenti ndi yofooka kwambiri, koma imakhala ndi mphamvu yofooka pakusintha kutentha kwa kutentha kwa hydration ya tricalcium aluminate. Cellulose ether adzakhala adsorbed ndi mankhwala ena hydration, motero kuchedwa ndi crystallization wa mankhwala hydration, ndiyeno zimakhudza hydration kutentha kumasulidwa mlingo wa simenti ndi ore limodzi.

Mawu ofunikira:cellulose ether; Simenti; Ore limodzi; Kutentha kwa hydration; kutsatsa

1. Mawu Oyamba

Ma cellulose ether ndi chinthu chofunikira chokhuthala komanso chosungira madzi mumatope osakanizika owuma, konkire yodzipangira yokha ndi zida zina zatsopano zopangira simenti. Komabe, ether ya cellulose idzachedwetsanso simenti ya hydration, yomwe imathandizira kukonza nthawi yogwiritsira ntchito zinthu zopangira simenti, kukonza kusasinthika kwamatope komanso kutayika kwa nthawi ya konkire, komanso kungachedwetse ntchito yomanga. Makamaka, zidzakhala ndi zotsatira zoipa pa matope ndi konkire zomwe zimagwiritsidwa ntchito mu malo otsika kutentha. Chifukwa chake, ndikofunikira kumvetsetsa lamulo la cellulose ether pa simenti ya hydration kinetics.

OU ndi Pourchez anaphunzira mwadongosolo zotsatira za magawo a maselo monga kulemera kwa maselo a cellulose ether, mtundu wa cholowa m'malo mwa simenti ya hydration kinetics, ndipo anapeza mfundo zambiri zofunika: Kukhoza kwa hydroxyethyl cellulose ether (HEC) kuchedwetsa hydration simenti nthawi zambiri imakhala yamphamvu kuposa ya methyl cellulose ether (HPMC), hydroxymethyl ethyl cellulose ether (HEMC) ndi methyl cellulose ether (MC). Mu cellulose ether yomwe ili ndi methyl, kutsika kwa methyl, kumapangitsa kuti athe kuchedwetsa hydration ya simenti; Kutsika kwa maselo olemera a cellulose ether, kumapangitsanso mphamvu yochepetsera kuyamwa kwa simenti. Zotsatirazi zimapereka maziko asayansi posankha cellulose ether molondola.

Kwa zigawo zosiyanasiyana za simenti, zotsatira za cellulose ether pa simenti hydration kinetics ndizovuta kwambiri pazantchito zamainjiniya. Komabe, palibe kafukufuku pankhaniyi. Mu pepalali, chikoka cha cellulose etha pa hydration kinetics wamba Portland simenti, C3S(tricalcium silicate), C3A(tricalcium aluminiyamu) ndi sulfoaluminate simenti (SAC) anaphunzira kudzera isothermal calorimetry mayeso, kuti mumve zambiri kugwirizana ndi. makina amkati pakati pa cellulose ether ndi simenti hydration mankhwala. Amaperekanso maziko asayansi ogwiritsiridwa ntchito moyenera kwa cellulose ether muzinthu zopangira simenti komanso amaperekanso maziko ofufuza a kugwirizana pakati pa zosakaniza zina ndi zinthu za simenti za simenti.

2. Mayeso

2.1 Zida Zopangira

(1) simenti wamba ku Portland (P · 0). Wopangidwa ndi Wuhan Huaxin Cement Co., LTD., mawonekedwe ake ndi P · 042.5 (GB 175-2007), yotsimikiziridwa ndi mawonekedwe amtundu wa X-ray fluorescence spectrometer (AXIOS advanced, PANalytical Co., LTD.). Malinga ndi kuwunika kwa pulogalamu ya JADE 5.0, kuwonjezera pa mchere wa simenti C3S, C2s, C3A, C4AF ndi gypsum, zida za simenti zimaphatikizansopo calcium carbonate.

(2) sulfoaluminate simenti (SAC). Simenti yolimba kwambiri ya sulfoaluminate yopangidwa ndi Zhengzhou Wang Lou Cement Industry Co., Ltd. ndi R.Star 42.5 (GB 20472-2006). Magulu ake akuluakulu ndi calcium sulfoaluminate ndi dicalcium silicate.

(3) tricalcium silicate (C3S). Press Ca(OH)2, SiO2, Co2O3 ndi H2O pa 3:1:0.08: Chiŵerengero cha misa cha 10 chinasakanizidwa mofanana ndi kukanikizidwa pansi pa kukakamizidwa kosalekeza kwa 60MPa kuti apange cylindrical green billet. The billet calcined pa 1400 ℃ kwa 1.5 ~ 2 h mu silicon-molybdenum ndodo mkulu kutentha magetsi ng'anjo, ndiyeno anasamukira mu uvuni mayikirowevu kuti zina mayikirowevu Kutentha kwa 40min. Pambuyo potulutsa billet, idazizidwa mwadzidzidzi ndikusweka mobwerezabwereza mpaka zomwe zili mu CaO yaulere muzomaliza zinali zosakwana 1.0%.

(4) tricalcium aluminiyamu (c3A). CaO ndi A12O3 zinasakanizidwa mofanana, zowerengeka pa 1450 ℃ kwa 4 h mu ng'anjo yamagetsi ya silicon-molybdenum, pansi mpaka ufa, ndi kuwerengeredwa mobwerezabwereza mpaka zomwe CaO yaulere inali yosakwana 1.0%, ndipo nsonga za C12A7 ndi CA zinali kunyalanyazidwa.

(5) cellulose ether. Ntchito yapitayi poyerekeza zotsatira za 16 mitundu ya mapadi etha pa hydration ndi kutentha kumasulidwa mlingo wamba Portland simenti, ndipo anapeza kuti mitundu yosiyanasiyana ya mapadi etha ndi kusiyana kwakukulu pa hydration ndi kutentha kumasulidwa lamulo la simenti, ndi kusanthula limagwirira mkati. kusiyana kwakukulu uku. Malinga ndi zotsatira za kafukufuku wam'mbuyomu, mitundu itatu ya ether ya cellulose yomwe ili ndi zotsatira zowoneka bwino pa simenti wamba ya Portland idasankhidwa. Izi zikuphatikizapo hydroxyethyl cellulose ether (HEC), hydroxypropyl methyl cellulose ether (HPMC), ndi hydroxyethyl methyl cellulose ether (HEMC). Kukhuthala kwa cellulose ether kunayesedwa ndi viscometer yozungulira yokhala ndi mayeso a 2%, kutentha kwa 20 ℃ ndi liwiro la 12 r/min. Kukhuthala kwa cellulose ether kunayesedwa ndi viscometer yozungulira yokhala ndi mayeso a 2%, kutentha kwa 20 ℃ ndi liwiro la 12 r/min. Digiri ya molar m'malo mwa cellulose ether imaperekedwa ndi wopanga.

(6) Madzi. Gwiritsani ntchito madzi achiwiri osungunuka.

2.2 Njira yoyesera

Kutentha kwa hydration. TAM Air 8-channel isothermal calorimeter yopangidwa ndi TA Instrument Company idakhazikitsidwa. Zida zonse zopangira zidasungidwa kutentha kwanthawi zonse kuyesa kutentha (monga (20± 0.5) ℃) kusanachitike. Choyamba, 3 g simenti ndi 18 mg cellulose ether ufa zinawonjezeredwa mu calorimeter (chiŵerengero cha misa cha cellulose ether ku cemellative material chinali 0.6%). Pambuyo kusakaniza kwathunthu, madzi osakaniza (madzi osungunuka achiwiri) anawonjezeredwa molingana ndi chiŵerengero cha simenti yamadzi ndi kusonkhezera mofanana. Kenako, idayikidwa mwachangu mu calorimeter kuti iyesedwe. Chiŵerengero cha madzi chomangira madzi cha c3A ndi 1.1, ndipo chiŵerengero cha madzi chomangira madzi cha zipangizo zina zitatu za simenti ndi 0.45.

3. Zotsatira ndi zokambirana

3.1 Zotsatira za mayeso

Zotsatira za HEC, HPMC ndi HEMC pa kutulutsa kutentha kwa hydration ndi kuchuluka kwa kutentha kwa simenti ya Portland, C3S ndi C3A mkati mwa maola 72, ndi zotsatira za HEC pa kutentha kwa hydration kutentha ndi kuchuluka kwa kutentha kwa simenti ya sulfoaluminate. mkati mwa 72 h, HEC ndi cellulose ether yomwe ili ndi mphamvu yochedwa kwambiri pa hydration ya simenti ina ndi ore imodzi. Kuphatikiza zotsatira ziwirizi, zitha kupezeka kuti ndikusintha kwa zinthu za cementitious, ether ya cellulose imakhala ndi zotsatira zosiyana pamlingo wotulutsa kutentha kwa hydration komanso kutulutsidwa kwa kutentha. The anasankha mapadi efa akhoza kwambiri kuchepetsa hydration ndi kutentha kumasulidwa mlingo wamba Portland simenti ndi C, S, makamaka prolongs nthawi kupatsidwa ulemu, kuchedwa kuoneka hydration ndi kutentha kumasulidwa pachimake, pakati pa mapalo efa C, S hydration ndi Kuchedwa kwa kutentha kwa kutentha kumawonekera kwambiri kuposa kutsika kwa simenti ya Portland ndi kuchedwa kwa kutentha kwa kutentha; Ma cellulose ether amathanso kuchedwetsa kutentha kwa sulfoaluminate simenti hydration, koma kuthekera kochedwa kumakhala kofooka kwambiri, ndipo makamaka kuchedwetsa hydration pambuyo pa 2 h; Pakutulutsa kutentha kwa C3A hydration, cellulose ether ili ndi mphamvu yofooka yothamangitsa.

3.2 Kusanthula ndi kukambirana

Limagwirira wa cellulosic etha kuchedwa simenti hydration. Silva et al. analingalira kuti cellulosic ether imachulukitsa kukhuthala kwa pore yankho ndikulepheretsa kuthamanga kwa ma ionic, motero kuchedwetsa simenti kuthira madzi. Komabe, zolembedwa zambiri zakayikira lingaliro ili, popeza zoyeserera zawo zapeza kuti ma cellulose ether okhala ndi mamasukidwe otsika amakhala ndi mphamvu yolimba yochepetsera simenti ya simenti. Ndipotu, nthawi ya kayendedwe ka ion kapena kusamuka ndi yochepa kwambiri moti mwachiwonekere sichingafanane ndi nthawi ya kuchedwa kwa simenti. Kutsatsa pakati pa cellulose ether ndi simenti hydration mankhwala amaonedwa kuti ndi chifukwa chenicheni cha kuchedwa kwa simenti hydration ndi cellulose ether. Cellulose ether mosavuta adsorbed pamwamba hydration mankhwala monga kashiamu hydroxide, CSH gel osakaniza ndi kashiamu aluminate hydrate, koma si zophweka adsorbed ndi ettringite ndi unhydrated gawo, ndi mphamvu adsorption wa cellulose efa pa calcium hydroxide ndi apamwamba kuposa ndi CSH gel. Chifukwa chake, pazinthu wamba za simenti ya Portland, ether ya cellulose imakhala ndi kuchedwa kwamphamvu kwambiri pa calcium hydroxide, kuchedwa kwambiri pa calcium, kuchedwa kwachiwiri pa CSH gel, komanso kuchedwa kofooka pa ettringite.

Kafukufuku wam'mbuyomu awonetsa kuti kutengeka pakati pa non-ionic polysaccharide ndi gawo la mineral makamaka kumaphatikizapo hydrogen bonding ndi chemical complexation, ndipo zotsatira ziwirizi zimachitika pakati pa gulu la hydroxyl la polysaccharide ndi chitsulo hydroxide pamtunda wa mchere. Liu et al. adayikanso ma adsorption pakati pa ma polysaccharides ndi ma hydroxides zitsulo monga kuyanjana kwa acid-base, ndi ma polysaccharides ngati ma acid ndi ma hydroxide achitsulo ngati maziko. Kwa polysaccharide yopatsidwa, kuchuluka kwa mchere wamchere kumatsimikizira mphamvu ya mgwirizano pakati pa ma polysaccharides ndi mchere. Pakati pa zigawo zinayi za gelling zomwe zaphunziridwa mu pepalali, zitsulo zazikulu kapena zopanda zitsulo zimaphatikizapo Ca, Al ndi Si. Malinga ndi dongosolo la ntchito zachitsulo, alkalinity ya ma hydroxides awo ndi Ca(OH)2>Al(OH3>Si(OH)4.M'malo mwake,Si(OH)4 solution ndi acidic ndipo samatsatsa cellulose ether. Zomwe zili mu Ca(OH)2 pamwamba pa zinthu za simenti za hydration zimatsimikizira mphamvu ya adsorption ya mankhwala a hydration ndi cellulose ether Chifukwa calcium hydroxide, CSH gel (3CaO · 2SiO2 · 3H20), ettringite (3CaO · Al2O3 · 3CaSO4 · 32H2O) ndi calcium aluminate hydrate (3CaO · Al2O3 · 6H2O) zili mu oxides zosawerengeka wa CaO ndi 100%, 58.33%, 49,56% ndi 62 .2%. aluminate > CSH gel > ettringite, zomwe zimagwirizana ndi zotsatira m'mabuku.

Mankhwala a hydration a c3S makamaka amaphatikizapo Ca(OH) ndi gel osakaniza a csH, ndipo cellulose ether imakhala ndi kuchedwa kwabwino pa iwo. Chifukwa chake, ether ya cellulose imakhala ndi kuchedwa koonekeratu pa C3s hydration. Kupatula c3S, simenti wamba ya Portland imaphatikizansopo C2s hydration yomwe imakhala yocheperako, zomwe zimapangitsa kuti kuchedwa kwa cellulose ether kusadziwike koyambirira. Ma hydration a silicate wamba amaphatikizanso ettringite, ndipo kuchedwa kwa cellulose ether ndikosavuta. Chifukwa chake, kuchedwa kwa cellulose ether kupita ku c3s ndikolimba kuposa simenti wamba ya Portland yomwe idawonedwa pakuyesa.

C3A idzasungunuka ndi kuthira madzi mofulumira ikakumana ndi madzi, ndipo mankhwala a hydration nthawi zambiri amakhala C2AH8 ndi c4AH13, ndipo kutentha kwa hydration kudzatulutsidwa. Pamene yankho la C2AH8 ndi c4AH13 lifika pa machulukidwe, crystallization ya C2AH8 ndi C4AH13 hexagonal sheet hydrate idzapangidwa, ndipo momwe zimakhalira ndi kutentha kwa hydration zidzachepetsedwa nthawi yomweyo. Chifukwa cha kutengeka kwa cellulose etha pamwamba pa calcium aluminate hydrate (CxAHy), kupezeka kwa cellulose ether kungachedwetse kusungunuka kwa C2AH8 ndi C4AH13 hexagonal-plate hydrate, zomwe zimapangitsa kuchepa kwa kachitidwe ndi kutentha kwa hydration kuposa pamenepo. wa C3A koyera, zomwe zimasonyeza kuti cellulose ether ali ndi mphamvu mathamangitsidwe ofooka C3A hydration. Ndikoyenera kudziwa kuti mu mayesowa, cellulose ether ali ndi mphamvu yofooka yothamangitsira ku hydration ya c3A yoyera. Komabe, mu simenti wamba ya Portland, chifukwa c3A idzachitapo kanthu ndi gypsum kuti ipange ettringite, chifukwa cha mphamvu ya ca2 + mu slurry solution, cellulose ether idzachedwetsa mapangidwe a ettringite, motero akuchedwa kuchepetsa c3A.

Kuchokera ku zotsatira za HEC, HPMC ndi HEMC pa hydration ndi kutentha kumasulidwa mlingo ndi cumulative kutentha kumasulidwa wamba Portland simenti, C3S ndi C3A mkati 72 h, ndi zotsatira za HEC pa hydration ndi kutentha kumasulidwa mlingo ndi cumulative kutentha kumasulidwa kwa sulfoaluminate. simenti mkati mwa 72 h, zikhoza kuwoneka kuti pakati pa atatu a cellulose ethers osankhidwa, Kukhoza kwa kuchedwa kwa hydration ya c3s ndi simenti ya Portland kunali kolimba kwambiri ku HEC, kutsatiridwa ndi HEMC, ndi kufooka kwambiri ku HPMC. Malingana ndi C3A, mphamvu ya ma cellulose ethers kuti ifulumizitse hydration imakhalanso mu dongosolo lomwelo, ndiye kuti, HEC ndi yamphamvu kwambiri, HEMC ndi yachiwiri, HPMC ndi yofooka komanso yamphamvu kwambiri. Izi zinatsimikizira kuti cellulose ether yachedwetsa mapangidwe a hydration mankhwala a gelling materials.

Zinthu zazikulu za simenti ya sulfoaluminate ndi ettringite ndi Al(OH) 3 gel. C2S mu simenti ya sulfoaluminate idzakhalanso ndi madzi padera kuti ipange Ca(OH)2 ndi cSH gel. Chifukwa adsorption wa mapadi efa ndi ettringite akhoza kunyalanyazidwa, ndi hydration wa sulfoaluminate mofulumira kwambiri, choncho, pa siteji yoyambirira ya hydration, mapadi ether ali ndi zotsatira zochepa pa hydration kutentha kumasulidwa mlingo wa sulfoaluminate simenti. Koma mpaka nthawi ina ya hydration, chifukwa c2s adzakhala padera hydrate kupanga Ca(OH)2 ndi CSH gel osakaniza, zinthu ziwirizi hydration adzakhala kuchedwa ndi mapadi ether. Chifukwa chake, zidawoneka kuti cellulose ether idachedwetsa hydration ya simenti ya sulfoaluminate pambuyo pa 2 h.

4. Mapeto

Mu pepala ili, kupyolera muyeso la isothermal calorimetry, lamulo lachikoka ndi mapangidwe a cellulose ether pa kutentha kwa hydration wamba wa Portland simenti, c3s, c3A, simenti ya sulfoaluminate ndi zigawo zina zosiyana ndi ore imodzi mu 72 h zinafaniziridwa. Mfundo zazikuluzikulu ndi izi:

(1) Cellulose ether akhoza kwambiri kuchepetsa hydration kutentha kumasulidwa mlingo wamba Portland simenti ndi tricalcium silicate, ndi zotsatira za kuchepetsa hydration kutentha kumasulidwa mlingo wa tricalcium silicate ndi yofunika kwambiri; Mphamvu ya cellulose ether pa kuchepetsa kutentha kwa simenti ya sulfoaluminate ndi yofooka kwambiri, koma imakhala ndi mphamvu yofooka pakusintha kutentha kwa tricalcium aluminate.

(2) cellulose ether adzakhala adsorbed ndi mankhwala ena hydration, motero kuchedwa crystallization wa mankhwala hydration, zimakhudza kutentha kutulutsa mlingo wa simenti hydration. Mtundu ndi kuchuluka kwa mankhwala hydration ndi osiyana zigawo zikuluzikulu za simenti bilu ore, kotero zotsatira za mapadi efa pa kutentha hydration awo si chimodzimodzi.